CFP - Docs - mDiscardRange

mDiscardRange

(range: Range) => (anArray: array) => anArray

Discard a range of elements

Ranges in Common FP are inclusive

Consider discardRange instead.
This is for the uncommon case where mutating anArray is required.

Try It

const range = { startIdx: 1, endIdx: 2 }
const mDiscard2ndAnd3rd = mDiscardRange(range)

const arr = [1, 2, 3, 4]
const mutatedArr = mDiscard2ndAnd3rd(arr)
console.log(mutatedArr === arr) // is true
console.log(arr) // is [1, 4]
const range = { startIdx: 1, endIdx: 2 }
const mDiscard2ndAnd3rd = mDiscardRange(range)

const arr = [1, 2, 3, 4]
const mutatedArr = mDiscard2ndAnd3rd(arr)
console.log(mutatedArr === arr) // is true
console.log(arr) // is [1, 4]

Try It

const range = { startIdx: 1, endIdx: 2 }
const mDiscard2ndAnd3rd = mDiscardRange(range)

const arr = [1, 2, 3, 4]
const mutatedArr = mDiscard2ndAnd3rd(arr)
console.log(mutatedArr === arr) // is true
console.log(arr) // is [1, 4]
const range = { startIdx: 1, endIdx: 2 }
const mDiscard2ndAnd3rd = mDiscardRange(range)

const arr = [1, 2, 3, 4]
const mutatedArr = mDiscard2ndAnd3rd(arr)
console.log(mutatedArr === arr) // is true
console.log(arr) // is [1, 4]

Sometimes we want to remove a range of elements. Below, we track the number of page visits to our site. Unfortunately, a bot generated an abnormally high number of visits for two hours. We stopped the bot; now let's remove those visits and calculate our hourly average.

Try It

const hourlyVisitors = [108, 125, 149, 163, 8692, 9154, 312, 356]

const hours5and6 = { startIdx: 4, endIdx: 5 }
const removeBotVisitors = mDiscardRange(hours5and6)
removeBotVisitors(hourlyVisitors)

const getAverageVisitors = compose([getAverageValue, roundToNearest('1')])

const hourlyAverage = getAverageVisitors(hourlyVisitors)
console.log(hourlyAverage) // is 202
const hourlyVisitors = [108, 125, 149, 163, 8692, 9154, 312, 356]

const hours5and6 = { startIdx: 4, endIdx: 5 }
const removeBotVisitors = mDiscardRange(hours5and6)
removeBotVisitors(hourlyVisitors)

const getAverageVisitors = compose([
  getAverageValue<number[]>,
  roundToNearest('1'),
])

const hourlyAverage = getAverageVisitors(hourlyVisitors)
console.log(hourlyAverage) // is 202

Try It

const hourlyVisitors = [
  108, 125, 149, 163, 8692, 9154, 312, 356,
]

const hours5and6 = { startIdx: 4, endIdx: 5 }
const removeBotVisitors =
  mDiscardRange(hours5and6)
removeBotVisitors(hourlyVisitors)

const getAverageVisitors = compose([
  getAverageValue,
  roundToNearest('1'),
])

const hourlyAverage = getAverageVisitors(
  hourlyVisitors
)
console.log(hourlyAverage) // is 202
const hourlyVisitors = [
  108, 125, 149, 163, 8692, 9154, 312, 356,
]

const hours5and6 = { startIdx: 4, endIdx: 5 }
const removeBotVisitors =
  mDiscardRange(hours5and6)
removeBotVisitors(hourlyVisitors)

const getAverageVisitors = compose([
  getAverageValue<number[]>,
  roundToNearest('1'),
])

const hourlyAverage = getAverageVisitors(
  hourlyVisitors
)
console.log(hourlyAverage) // is 202